A Mexican judge ordered 12 federal police officers held without bail for 40 days pending an investigation of last week's attack by cops on a U.S. Embassy vehicle, the Attorney General's Office said Monday.

Two embassy personnel and an official of the Mexican navy department traveling with them were wounded in the incident, but none of the injuries was life-threatening.

Prosecutors sought the extended pre-charge detention "to have the time necessary to conduct an exhaustive investigation with collaboration from all levels," Attorney General Marisela Morales told reporters.

She said her office is working "with each and every national and international authority" to determine what happened last Friday.

Police were engaged in anti-crime operations at the time of the assault on the U.S. Embassy vehicle, a Toyota SUV with diplomatic plates, the Mexican government said last Friday in a statement.

The Americans and the Mexican official were traveling on a stretch of unpaved road en route to a navy installation at El Capulin mountain when they encountered "a vehicle whose occupants brandished guns," the statement said.

The driver of the Toyota "maneuvered to get away and re-enter the highway, the moment in which the occupants of the aggressor vehicle opened fire on the diplomatic vehicle."

Soon, according to the statement, "three other vehicles joined the pursuit and fired gunshots at the U.S. Embassy vehicle."

The two U.S. officials were taken under police escort to a hospital in Cuernavaca, roughly 85 kilometers (53 miles) south of Mexico City.

The cops involved in the shooting were taken into custody within hours of the incident. EFE